This noun is one of several Azerbaijani nouns which lose their last vowel in the accusative, genitive and dative singular, and in the singular possessive forms (see more Azerbaijani nouns which lose their last vowel).
^ 张, 进锋 (Ayso Cañ Cinfen) (2008) 乌璐别格 (Ulubeğ), 鄭初陽 (Çuyañ Yebey oğlı Ceñ), editors, Salar İbret Sözler 撒拉尔谚语 [Salar Proverbs][1], China Salar Youth League, page 54
Potanin, G.N. (1893) “ağız”, in Тангутско-Тибетская окраина Китая и Центральная Монголия (in Russian), pages 428, 430
Yanchuk, Mikola Andriyovich (1893) Этнографическое ОбозрѢніе: Императорскаго Общества Любителей Естествознанія, Антропологіи и Этнографіи [Ethnographical Review: Imperial Society of Lovers of Natural History, Anthropology and Ethnography][2] (in Russian), Moscow: Publication of the Ethnographic Department, page 33
Rockhill, William Woodville (1894) “aks”, in Diary of a journey through Mongolia and Tibet in 1891 and 1892, Washington: Smithsonian Institution, page 374
Poppe, Nicholas (1953). Remarks on The Salar Language. Harvard Journal of Asiatic Studies, 16(3/4), 438–477. [3]
Kakuk, S. (1962) “ağız”, in “Un Vocabulaire Salar”, in Acta Orientalia Academiae Scientiarum Hungaricae[4], volume 14, number 2, Akadémiai Kiadó, →ISBN, pages 173-196
林莲云 [Lin Lianyun] (1985) “ağız”, in 撒拉语简志 [A Brief History of Salar][5], Beijing: 民族出版社: 琴書店, →OCLC, page 123
Tenishev, Edhem (1976) “āɣyz, agyz”, in Stroj salárskovo jazyká [Grammar of Salar], Moscow, pages 282, 283
Yakup, Abdurishid (2002) “ağız”, in An Ili Salar Vocabulary: Introduction and a Provisional Salar-English Lexicon[6], Tokyo: University of Tokyo, →ISBN, pages 34, 36